Optical Properties of the Retinal Receptors*†

Enoch, Jay M.

doi:10.1364/josa.53.000071

Cited by 193 publications

(101 citation statements)

References 58 publications

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“…3d). We also applied our algorithm to cones and found it to match perfectly previous results for light propagation along these cells 23,[40][41][42] , which were obtained and examined by other methods such as coupled mode theory 22,[43][44][45] .…”

Section: Methodssupporting

confidence: 63%

Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision

et al. 2014

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Vision starts with the absorption of light by the retinal photoreceptors-cones and rods. However, due to the 'inverted' structure of the retina, the incident light must propagate through reflecting and scattering cellular layers before reaching the photoreceptors. It has been recently suggested that Müller cells function as optical fibres in the retina, transferring light illuminating the retinal surface onto the cone photoreceptors. Here we show that Müller cells are wavelength-dependent wave-guides, concentrating the green-red part of the visible spectrum onto cones and allowing the blue-purple part to leak onto nearby rods. This phenomenon is observed in the isolated retina and explained by a computational model, for the guinea pig and the human parafoveal retina. Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision.

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Section: Methodssupporting

confidence: 63%

Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision

et al. 2014

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“…In this framework, the scattering properties of the structures present at the position of the focused point source in the retina govern the proportion of light that falls within and outside the confocal detection area. For example, the strong waveguide properties of cones (46,47) ensure that a large proportion of the light that returns from the photoreceptor layer is highly directionally backscattered, making them particularly well-suited targets for confocal imaging; empirical results are consistent with this expectation.…”

Section: Discussionmentioning

confidence: 85%

Imaging individual neurons in the retinal ganglion cell layer of the living eye

Rossi

Granger

Sharma

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

174

151

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Although imaging of the living retina with adaptive optics scanning light ophthalmoscopy (AOSLO) provides microscopic access to individual cells, such as photoreceptors, retinal pigment epithelial cells, and blood cells in the retinal vasculature, other important cell classes, such as retinal ganglion cells, have proven much more challenging to image. The near transparency of inner retinal cells is advantageous for vision, as light must pass through them to reach the photoreceptors, but it has prevented them from being directly imaged in vivo. Here we show that the individual somas of neurons within the retinal ganglion cell (RGC) layer can be imaged with a modification of confocal AOSLO, in both monkeys and humans. Human images of RGC layer neurons did not match the quality of monkey images for several reasons, including safety concerns that limited the light levels permissible for human imaging. We also show that the same technique applied to the photoreceptor layer can resolve ambiguity about cone survival in age-related macular degeneration. The capability to noninvasively image RGC layer neurons in the living eye may one day allow for a better understanding of diseases, such as glaucoma, and accelerate the development of therapeutic strategies that aim to protect these cells. This method may also prove useful for imaging other structures, such as neurons in the brain.

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“…The single ring pattern found by Enoch (1963) is not necessarily a 'IX,,, or a TMo,, or a HE,,, mode, but the pattern may even be a combination of the HEIvI and the WEI,* mode. This combination is pkne polarized with a plane of pohrization determined by the incident field.…”

Section: Numerical Resultsmentioning

confidence: 91%

“…To obtain patterns qualitatively comparable to the patterns observed by Enoch (1963) at the terminations of retinal receptors I: was chosen to be 45 for i,,, = 400 nm. A representative value of 6 for cone outer segments is 0.072; this implies a value for p of 0.768 pm.…”

Section: Numerical Resultsmentioning

confidence: 99%

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Mode interference patterns in retinal receptor outer segments

Wijngaard

1974

Vision Research

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Abstract-Some calculated interference patterns of electromagnetic modes are given for a dielectric waveguide representative for the receptor outer segment. The results are qualitatively in accordance with observations of Enoch.Retinal receptors are lightguiding structures of relatively small dia, in which the energy is guided in patterns called modes (Enoch, 1963). These modes have a definite phasevelocity. However, generally some modes with d&rent phaseveloeities occur inside the receptor outer segment. In this case the modes interfere with a different phase at different levels along the outer segment.For some cases interference patterns of guided modes were calculated. Results qualitatively in aceordante with some observations of Enoch (1963) were obtained. THEORYThe receptor outer segment was approximated by a homogeneous isotropic circular cylindrical dielectric rod (Fig. 1). Apart from guided modes there are unguided modes which are not bound to the receptor. These unguided modes wig not be considered here. The characteristics of the guided modes are determined by the normalized frequency u = (Znpn,/l,,)JG and 8. Here d = 1 -(n:/n:); n, and n2 are the refractive indices of the inside and outside medium respectively, p is the radius of the rod and )LnC is the vacuum wavelength of the incident light. For retinal receptors the parameter S is of the order of @l, therefore the approx results for 6-0 may be used for the field of the modes (Snyder, 1969a). The amplitude with which a mode is excited may be calculated neglecting the reflected light (Snyder, 1969b). In this approximation when the light incident on the outer segment is plane polar&d, plane polarized modes and modecombinations are excited (Wijngaard, 1971). Interference effects can only be obtained when the phasevelocity of the modes is different, therefore the approximation 6 + 0 is not applicable to calculations of the phasevelocity. However, the difference in phasevelocitpbetween the modes of a plane polarized mode-combination is small enough to conserve the plane polarixation when the modes are guided along the outer segment.The author has discussed minor deviations from this result for frog rods (Wijngaard. 1971). The approximate conservance of the plane and the degree of polarization is characteristic for the relatively short fibres of small 6 in the retina. For the much longer fibres of, for example, Snitxer and Osterberg (1961) this may not be the case. These remarks should be considered in the designation of modes to patterns observed in retinal receptor outer segments.To obtain physiologically significant interference patterns the amplitudes of the modes should be calculated from the field incident on the retina. However, even for an incident plane wave this problem is complex owing to the influence of the inner segment. Therefore the field at the entrance of the outer segment was assumed to be a plane wave restricted to the outer segment with the electric field vector perpendicular to the plane of incidence. The propagation vector k of the p...

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Optical Properties of the Retinal Receptors*†

Cited by 193 publications

References 58 publications

Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision

Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision

Imaging individual neurons in the retinal ganglion cell layer of the living eye

Mode interference patterns in retinal receptor outer segments

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